Some confusions about bishop

Hi Guys! I need some clarification with the bishop skill here
According to the descriptions, bishop's Angel Ray skill could reduce enemies' defense by maximum 40%. I am wondering, if such could work on all enemies including bosses like Lucid or Will who got a 300% defense? And if so, how should I calculate this, should I go with 300% - 40%, or 300% * (1 - 40%) (which seems unlikely to me)?
Also, can this defense reduction be counted as debuff? More specifically, could this effect triger some link skills from like explorer thieves or cadena?
Many thanks in advance for your time!

December 31, 2020